The move comes as a surprise after Anderson piled up 1,500 yards over the past two seasons. The original-round designation means Denver can only match any offer Anderson receives. If they let him sign elsewhere, the Broncos get nothing in return.

Anderson is a streaky runner, but he showed the DNA of a big-game back down the stretch in 2014, and played well in spots last season. With Ronnie Hillman also set to hit the open market, though, Denver appears open to starting over in the backfield.

It's fair to wonder if coach Gary Kubiak still has eyes for Arian Foster, his former Texans star back who was released by Houston last week. If not, the Broncos can explore this year's deep class of free-agent runners if Anderson ultimately slips away.